利妥昔单抗及其生物类似药的杂质分析

目的  对利妥昔单抗原研药和类似药的产品相关杂质和工艺相关杂质进行分析。方法 用分子排阻高效液相色谱法（size-exclusion high-performance liquid chromatography，SE-HPLC）、毛细管电泳和离子交换高效液相色谱法（ion-exchange high-performance liquid chromatography，IEX-HPLC）对原研药和类似药的产品相关杂质进行分析。同时对类似药的电荷异质体进行纯度和生物活性鉴定。采用ELISA和定量PCR对原研药和类似药的工艺相关杂质进行分析。结果 SE-HPLC分析表明，原研药和类似药中抗体单体分别占98.9%和99.9%，聚合体分别占1.0%和0.1%。毛细管电泳显示，原研药中相对分子质量低的杂质占5.6%，类似药中占3.3%；原研药和类似药中非糖基化重链均占0.6%。IEX-HPLC分析表明，原研药酸性峰和碱性峰含量分别为21.0%和10.0%，类似药分别为17.7%和9.1%。类似药主峰组分的纯度和补体依赖的细胞毒性均高于酸性峰组分和碱性峰组分。原研药和类似药中的宿主细胞蛋白、宿主细胞DNA及蛋白A的残留量相似，且大多低于检测限。结论 利妥昔单抗原研药和类似药产品相关杂质和工艺相关杂质的类别和水平相似。

Impurity analysis of Rituximab and its biosimilar

Objective  To analyze product- and process-related impurities in original Rituximab and its biosimilar. Methods  Product-related impurities in Rituximab and its biosimilar were analyzed using size-exclusion high-performance liquid chromatography (SE-HPLC), capillary electrophoresis, and ion-exchange high-performance liquid chromatography (IEX-HPLC). Purity and biological activity of biosimilar charge variants were further determined. Process-related impurities in Rituximab and its biosimilar were analyzed using ELISA and quantitative PCR. Results  In SE-HPLC analysis, the antibody monomers in original Rituximab and its biosimilar were 98.9% and 99.9%, and polymers were 1.0% and 0.1%, respectively. The capillary electrophoresis showed that low molecular weight impurities were 5.6% in Rituximab and 3.3% in biosimilar, while non-glycosylated heavy chains were 0.6% in both. In IEX-HPLC analysis, acidic and basic peaks were 21.0% and 10.0% for Rituximab, and 17.7% and 9.1% for biosimilar. The main peak fraction of biosimilar had higher purity and complement-dependent cytotoxicity than both acidic and basic peak fractions. The residual of quantities host cell protein and DNA, and protein A were similar in Rituximab and its biosimilar, mostly below detection limits. Conclusion  Original Rituximab and its biosimilar have similar category and level of product- and process-related impurities.